In occasional use since 19th century, re-coined 2005 by team of Citigroup global strategist Ajay Kapur to describe economies with significant income and wealth inequality,[1] subsequently popularized.[2]

^“Plutonomics”, Robert Frank, Wall Street Journal blog The Wealth Report, January 8, 2007:
‘Ajay Kapur, global strategist at Citigroup, and his research team came up with the term “Plutonomy” in 2005 to describe a country that is defined by massive income and wealth inequality. According to their definition, the U.S. is a Plutonomy, along with the U.K., Canada and Australia.’